1. Technical Field
The invention relates to the manufacture of pneumatic tires and in particular to an apparatus and system for preventing a bladder release lubricant, which is sprayed on the innerliner of a green tire, from contaminating the innerliner splice. Even more particularly, the invention relates to the use of high pressure air for forming a barrier about the innerliner splice to prevent the release lubricant from contaminating the splice.
2. Background Information
During the manufacture of pneumatic tires, a green uncured tire is transferred from a tire assembly station to a spray station where a bladder release lubricant is sprayed about the interior of the tire onto the innerliner to prevent the innerliner from sticking to an inflatable bladder at a mold station to which the green tire is subsequently delivered. After the green tire has been placed in a curing mold and the mold sealed, a bladder is inflated to force the green tire against the heated mold walls whereby the tire is formed with a desired tread pattern. After a curing period, the bladder is deflated and the mold is opened and the cured tire is removed from the mold. However, problems have been encountered in that the bladder can stick to the innerliner of the tire, causing damage to the innerliner and/or bladder upon removal of the tire from the mold.
Therefore, to overcome this sticking problem, the green tire is first delivered to a spray station where a release lubricant is applied to the innerliner of the tire, which is that portion which contacts the expandable curing bladder. However, this lubricant could affect the tire if allowed to penetrate the innerliner splice which could result in the tire being rejected. Therefore, to avoid this problem, a mechanical barrier, such as a flexible fabric, is placed over the innerliner splice at the spray station to prevent the lubricant from contacting and contaminating the innerliner splice. However, the use of this mechanical device or covering fabric requires maintenance and increases the cycle time at the spray station.
Therefore, the need exists for an improved method and apparatus which is applied at the bladder release spray station to prevent the contamination of the innerliner splice by the sprayed lubricant, which is effective and which decreases maintenance and improves cycle time of the green tire moving through the spray station prior to entering a mold station.